1. Field of the Invention
This invention relates to an injection mold device, more particularly to an injection mold device including a stationary mold plate, a movable mold plate, and a stripper plate disposed between the stationary and movable mold plates.
2. Description of the Related Art
Referring to FIG. 1, a conventional three-plate injection mold device 1 includes a stationary mold plate 11, a movable mold plate 12, and a stripper plate 13 disposed between the stationary mold plate 11 and the movable mold plate 12. The stationary mold plate 11 has a bottom surface 114 and includes a sprue 111 and a sprue open end 112 formed in the bottom surface 114. The stripper plate 13 has opposite top and bottom ends 1311, 1312, a plurality of first runners 131 formed in the top end 1311, and a first forming part 132 formed in the bottom end 1312. The stripper plate 13 further has a plurality of second runners 133 that extend downwardly from the first runners 131 and that are in fluid communication with the first runners 131 and the first forming part 132. The movable mold plate 12 has an upper surface 122 and a second forming part 121 formed in the upper surface 122.
When the stationary mold plate 11, the stripper plate 13, and the movable mold plate 12 are assembled (not shown), the first and second forming parts 132, 121 form a mold cavity. Melted plastic material is injected into the sprue 111, and flows through the first and second runners 131, 133, into the mold cavity. When the melted plastic material is cooled, the plastic material in the mold cavity is formed into a molded part, but those remaining in the sprue 111, and the first and second runners 131, 133 become plastic scrap or waste material.
Since each of the second runners 133 in the conventional three-plate injection mold device 1 substantially extends from the top end 1311 to the bottom end 1312 of the stripper plate 13, the length of each of the second runners 133 is substantially identical to a thickness of the stripper plate 13. Therefore, the length of the plastic scrap or waste produced in each second runner 133 is substantially as large as the thickness of the stripper plate 13 so that the amount of the plastic scrap or waste produced in the stripper plate 13 cannot be reduced, thereby increasing the manufacturing cost of products.